Abstract

Mitotic, meiotic and pollen studies were carried out on selected accessions of African yam bean (AYB).
Presented results confirmed diploid status of the species. Somatic chromosome counts of 2n= 22 (n=11)
were made in most of the accessions except TSs3 in which counts of 2n= 18 were made in some cells.
The somatic chromosomes were very small, mostly metacentric and submetacentric with distinct
centromeres. The smallness of the chromosomes made it very difficult for karyotype. Meiosis was
regular in most of the accessions with formation of 11 bivalents, except in TSs3 and TSs23 where some
univalents erratic chromosome movements were observed. The studies revealed a correlation between
meiotic irregularities and low pollen fertility. The limitations of the results of this study arose from the
notorious difficulty of studying legume chromosomes.